If it isn't good to suffer from diseases, why doesn't your deity resolve all of them immediately?
the true One is still in struggle with the "darkness" - He has to overcome the "darkness" completely and permanently, and not for Himself, but for humans and the souls in general - there are some things that you seem not to understand, for example it has been very typical of the system of human spirituality/religiosity to lay down and impose its own exaggerated terms of what God must be, as if God must create a rock so heavy that even He Himself cannot lift it, i am not trying to say that He is not omnipotent, however, omnipotent for what?! - can He afford to cause evil to humans/souls if He is really the true God?!, to put it another way, can He afford to be unrighteous/sinful/unholy/guilty if He is really the true God?!, and why must we entirely exclude the possibility that for some reason there may not be paradisaical life lasting for all the coming time's infinity for any soul?!, let's say the life of God also has a span/cycle, though He never dies completely, but His death is partial, and therefore He has periodically to start all over/from scratch, including with His struggle with the "darkness"...
however, it is written in Scripture that His struggle with the "darkness" cannot continue more than about 5-6 millennia as from the beginning of the little eternity:
Revelation 17:10 "there are seven kings(i.e. seven times): five are fallen(i.e. five millennia may pass as from the day of the Fall), and one is(i.e. and the end may come in the sixth millennium), and the other is not yet come(i.e. and the time for which evil may reign in the sixth millennium has not yet begun); and when he cometh, he must continue a short space(i.e. but its length will be short)."
How do you know (not simply believe or imagine) that you are practicing the true faith correctly, and not a Muslim, or a Hindu, or a Pagan?
how could for example St Paul be aware and confident of what he believes?!, as in:
Romans 14:14 "I know, and am persuaded by the Lord Jesus, that there is nothing unclean of itself: but to him that esteems any thing to be unclean, to him it is unclean."
there is something that is stronger than us, something innermost, something coming from and in the true One, it is hard to explain, but there is a "heart" and a mind that, albeit more or less inexplicable, is stronger than the world, of course in the good sense of the word, yet like the simple(st) equations such as 1+1=2, 2+2=4, etc. - only people that practice the faith right can witness to it the most among humans
Blessings